Eight years after telling mothers that going out to work and leaving their children in substitute care was harmful to children's development, academics combing through the same research material said this week that mothers should not worry after all.

This newest study was published last week by the U.S. Society for Research and Child Development. It was based -like the 2002 study -on data collected over several years on more than 1,300 children.

This year's findings showed that when the overall impact of a mother's participation in the paid workforce on her child's mental and social development was measured, the effect was neutral. The positives -higher family income, better child care, the mother's improved mental health -outweighed the negatives, such as less time for mother and baby to interact.

But the best of all worlds was not when mothers of young children stayed at home full-time, but rather when they work part-time. As the London Telegraph reported, children whose mothers worked fewer than 30 hours a week benefited from the higher household income, better quality daycare, a happier home-life, plus interaction with their mother.

This conclusion is a stunning turnaround from 2002, when the U.S. National Institutes of Health warned that children who spent long hours in child care could experience more stress and be at increased risk of developing behavioural problems. As the New York Times reported, problems included disobedience and aggressiveness.

The 2002 study, by the National Institute of Child Health and Human Development, seemed categorical: The longer a child spent in daycare, the more likely he was to have behaviour problems and the worse those problems would be.

I have taught Kindergarten for 11 years. The daycare kids are always better adjusted, have higher academic skills and much better social skills. They are also more independent. Obviously kids shouldn't spend long, long (10+) hours a day in care but daycare does NOT hurt children.